diff --git a/frontend/src/components/MaterialSidebar.tsx b/frontend/src/components/MaterialSidebar.tsx
index 9767c63..399d9d8 100644
--- a/frontend/src/components/MaterialSidebar.tsx
+++ b/frontend/src/components/MaterialSidebar.tsx
@@ -36,7 +36,8 @@ const verticalChrome = (el: HTMLElement): number => {
 const setChildrenById = (
     tags:     MaterialSidebarTag[],
     targetId: number,
-    children: MaterialSidebarTag[]): MaterialSidebarTag[] => (
+    children: MaterialSidebarTag[],
+): MaterialSidebarTag[] => (
     tags.map (tag => {
       if (tag.id === targetId)
 	return { ...tag, children }
diff --git a/frontend/src/pages/materials/MaterialListPage.tsx b/frontend/src/pages/materials/MaterialListPage.tsx
index 6a6da5c..f585df0 100644
--- a/frontend/src/pages/materials/MaterialListPage.tsx
+++ b/frontend/src/pages/materials/MaterialListPage.tsx
@@ -83,7 +83,8 @@ const materialTitle = (material: Material): string =>
 
 const groupedTagPath = (
     tagId: number,
-    materialFilter: MaterialFilter): string =>
+    materialFilter: MaterialFilter,
+): string =>
     `/materials?tag_id=${ tagId }&include_descendants=1&group_by=parent_tag`
     + `&material_filter=${ materialFilter }`